Question

What is the theoretical yield of ammonia (in grams) if 17.15 grams of nitrogen gas and 10.95 grams of hydrogen gas are allowed to react?

Based on your theoretical yield, what is the percent yield of ammonia if only 11.5 grams of ammonia is produced?

How much heat energy (in kJ) will be absorbed or released if 11.5 grams of ammonia is produced? State whether the energy will be absorbed or released.(use dimensional analysis)

Answer 1

N2 + 3H2 = 2NH3

mol of N2 = mass/MW = 17.15/17 = 1.0088

mol of H2 = mass/MW = 10.95/2 = 5.475

ratio is 1:3 so we have excess H2

max amount of NH# --> 2 mol of N2 = 2*1.0088 = 2.0176 mol of NH# can be produced

mass = mol*MW = 2.0176*17 = 34.2992 g of NH3

b)

% yield = actual / theoretical * !00% = 11.5/34.2992*100 = 33.5284 %

c)

find heat absorbed:

1 mol of NH3 --> -45.9 kJ

11.5 g--> 11.5/17 = 0.6764 mol of NH3

total heat released --> 0.6764 * 45.9 = 31.046 kJ will be released